The invention relates to a method for the taking of an image by a line sensor or an areal (or matrix) sensor, in particular a CCD sensor or a CMOS sensor, wherein the image is projected onto the sensor by an optical imaging system and is taken by the sensor. The invention further relates to a camera having a line sensor or an areal sensor, in particular a CCD sensor or a CMOS sensor, and an optical imaging system for the projection of an image onto the sensor.
Cameras of this type are already known. They can in particular be used in 3D measuring units. In these cameras, line sensors or areal sensors are used on which a plurality of photosensitive cells (pixels) are arranged in a regular manner, preferably in a rectangular or square manner. CCD sensors or CMOS sensors (CMOS chips or CMOS line sensors) are in particular used.
The resolution of such sensors is, however, limited. To increase the resolution, the number of pixels can be increased. When the pixel size remains the same, this results in larger sensors, whereby the influence of the optical aberrations becomes larger. When the pixels are made smaller, the signal-to-noise ratio of the image information is degraded.
To increase the resolution of the image, it is possible to displace the sensor by a specific fraction of the pixel spacing between two or more image shots, which can take place, for example, by a suitable actuator, for example a piezo-actuator.
Additional information is thereby gained at the positions between the original pixels. The effort for the displacement of the sensor is, however, very high.